sys/net/netisr.c

   1 /*
   2  * Copyright (c) 2003, 2004 Matthew Dillon. All rights reserved.
   3  * Copyright (c) 2003, 2004 Jeffrey M. Hsu.  All rights reserved.
   4  * Copyright (c) 2003 Jonathan Lemon.  All rights reserved.
   5  * Copyright (c) 2003, 2004 The DragonFly Project.  All rights reserved.
   6  *
   7  * This code is derived from software contributed to The DragonFly Project
   8  * by Jonathan Lemon, Jeffrey M. Hsu, and Matthew Dillon.
   9  *
  10  * Jonathan Lemon gave Jeffrey Hsu permission to combine his copyright
  11  * into this one around July 8 2004.
  12  *
  13  * Redistribution and use in source and binary forms, with or without
  14  * modification, are permitted provided that the following conditions
  15  * are met:
  16  * 1. Redistributions of source code must retain the above copyright
  17  *    notice, this list of conditions and the following disclaimer.
  18  * 2. Redistributions in binary form must reproduce the above copyright
  19  *    notice, this list of conditions and the following disclaimer in the
  20  *    documentation and/or other materials provided with the distribution.
  21  * 3. Neither the name of The DragonFly Project nor the names of its
  22  *    contributors may be used to endorse or promote products derived
  23  *    from this software without specific, prior written permission.
  24  *
  25  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
  26  * ``AS IS'' AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
  27  * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
  28  * FOR A PARTICULAR PURPOSE ARE DISCLAIMED.  IN NO EVENT SHALL THE
  29  * COPYRIGHT HOLDERS OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
  30  * INCIDENTAL, SPECIAL, EXEMPLARY OR CONSEQUENTIAL DAMAGES (INCLUDING,
  31  * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
  32  * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
  33  * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
  34  * OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
  35  * OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
  36  * SUCH DAMAGE.
  37  *
  38  * $DragonFly: src/sys/net/netisr.c,v 1.35 2007/07/10 20:24:57 dillon Exp $
  39  */
  40
  41 #include <sys/param.h>
  42 #include <sys/systm.h>
  43 #include <sys/kernel.h>
  44 #include <sys/malloc.h>
  45 #include <sys/msgport.h>
  46 #include <sys/proc.h>
  47 #include <sys/interrupt.h>
  48 #include <sys/socket.h>
  49 #include <sys/sysctl.h>
  50 #include <net/if.h>
  51 #include <net/if_var.h>
  52 #include <net/netisr.h>
  53 #include <machine/cpufunc.h>
  54
  55 #include <sys/thread2.h>
  56 #include <sys/msgport2.h>
  57 #include <net/netmsg2.h>
  58
  59 static void netmsg_sync_func(struct netmsg *msg);
  60
  61 struct netmsg_port_registration {
  62     TAILQ_ENTRY(netmsg_port_registration) npr_entry;
  63     lwkt_port_t npr_port;
  64 };
  65
  66 static struct netisr netisrs[NETISR_MAX];
  67 static TAILQ_HEAD(,netmsg_port_registration) netreglist;
  68
  69 /* Per-CPU thread to handle any protocol.  */
  70 struct thread netisr_cpu[MAXCPU];
  71 lwkt_port netisr_afree_rport;
  72 lwkt_port netisr_adone_rport;
  73 lwkt_port netisr_apanic_rport;
  74 lwkt_port netisr_sync_port;
  75
  76 static int (*netmsg_fwd_port_fn)(lwkt_port_t, lwkt_msg_t);
  77
  78 /*
  79  * netisr_afree_rport replymsg function, only used to handle async
  80  * messages which the sender has abandoned to their fate.
  81  */
  82 static void
  83 netisr_autofree_reply(lwkt_port_t port, lwkt_msg_t msg)
  84 {
  85     kfree(msg, M_LWKTMSG);
  86 }
  87
  88 /*
  89  * We need a custom putport function to handle the case where the
  90  * message target is the current thread's message port.  This case
  91  * can occur when the TCP or UDP stack does a direct callback to NFS and NFS
  92  * then turns around and executes a network operation synchronously.
  93  *
  94  * To prevent deadlocking, we must execute these self-referential messages
  95  * synchronously, effectively turning the message into a glorified direct
  96  * procedure call back into the protocol stack.  The operation must be
  97  * complete on return or we will deadlock, so panic if it isn't.
  98  */
  99 static int
 100 netmsg_put_port(lwkt_port_t port, lwkt_msg_t lmsg)
 101 {
 102     netmsg_t netmsg = (void *)lmsg;
 103
 104     if ((lmsg->ms_flags & MSGF_SYNC) && port == &curthread->td_msgport) {
 105         netmsg->nm_dispatch(netmsg);
 106         if ((lmsg->ms_flags & MSGF_DONE) == 0)
 107             panic("netmsg_put_port: self-referential deadlock on netport");
 108         return(EASYNC);
 109     } else {
 110         return(netmsg_fwd_port_fn(port, lmsg));
 111     }
 112 }
 113
 114 /*
 115  * UNIX DOMAIN sockets still have to run their uipc functions synchronously,
 116  * because they depend on the user proc context for a number of things
 117  * (like creds) which we have not yet incorporated into the message structure.
 118  *
 119  * However, we maintain or message/port abstraction.  Having a special
 120  * synchronous port which runs the commands synchronously gives us the
 121  * ability to serialize operations in one place later on when we start
 122  * removing the BGL.
 123  */
 124 static int
 125 netmsg_sync_putport(lwkt_port_t port, lwkt_msg_t lmsg)
 126 {
 127     netmsg_t netmsg = (void *)lmsg;
 128
 129     KKASSERT((lmsg->ms_flags & MSGF_DONE) == 0);
 130
 131     lmsg->ms_target_port = port;        /* required for abort */
 132     netmsg->nm_dispatch(netmsg);
 133     return(EASYNC);
 134 }
 135
 136 static void
 137 netisr_init(void)
 138 {
 139     int i;
 140
 141     TAILQ_INIT(&netreglist);
 142
 143     /*
 144      * Create default per-cpu threads for generic protocol handling.
 145      */
 146     for (i = 0; i < ncpus; ++i) {
 147         lwkt_create(netmsg_service_loop, NULL, NULL, &netisr_cpu[i], 0, i,
 148                     "netisr_cpu %d", i);
 149         netmsg_service_port_init(&netisr_cpu[i].td_msgport);
 150     }
 151
 152     /*
 153      * The netisr_afree_rport is a special reply port which automatically
 154      * frees the replied message.  The netisr_adone_rport simply marks
 155      * the message as being done.  The netisr_apanic_rport panics if
 156      * the message is replied to.
 157      */
 158     lwkt_initport_replyonly(&netisr_afree_rport, netisr_autofree_reply);
 159     lwkt_initport_replyonly_null(&netisr_adone_rport);
 160     lwkt_initport_panic(&netisr_apanic_rport);
 161
 162     /*
 163      * The netisr_syncport is a special port which executes the message
 164      * synchronously and waits for it if EASYNC is returned.
 165      */
 166     lwkt_initport_putonly(&netisr_sync_port, netmsg_sync_putport);
 167 }
 168
 169 SYSINIT(netisr, SI_SUB_PROTO_BEGIN, SI_ORDER_FIRST, netisr_init, NULL);
 170
 171 /*
 172  * Finish initializing the message port for a netmsg service.  This also
 173  * registers the port for synchronous cleanup operations such as when an
 174  * ifnet is being destroyed.  There is no deregistration API yet.
 175  */
 176 void
 177 netmsg_service_port_init(lwkt_port_t port)
 178 {
 179     struct netmsg_port_registration *reg;
 180
 181     /*
 182      * Override the putport function.  Our custom function checks for
 183      * self-references and executes such commands synchronously.
 184      */
 185     if (netmsg_fwd_port_fn == NULL)
 186         netmsg_fwd_port_fn = port->mp_putport;
 187     KKASSERT(netmsg_fwd_port_fn == port->mp_putport);
 188     port->mp_putport = netmsg_put_port;
 189
 190     /*
 191      * Keep track of ports using the netmsg API so we can synchronize
 192      * certain operations (such as freeing an ifnet structure) across all
 193      * consumers.
 194      */
 195     reg = kmalloc(sizeof(*reg), M_TEMP, M_WAITOK|M_ZERO);
 196     reg->npr_port = port;
 197     TAILQ_INSERT_TAIL(&netreglist, reg, npr_entry);
 198 }
 199
 200 /*
 201  * This function synchronizes the caller with all netmsg services.  For
 202  * example, if an interface is being removed we must make sure that all
 203  * packets related to that interface complete processing before the structure
 204  * can actually be freed.  This sort of synchronization is an alternative to
 205  * ref-counting the netif, removing the ref counting overhead in favor of
 206  * placing additional overhead in the netif freeing sequence (where it is
 207  * inconsequential).
 208  */
 209 void
 210 netmsg_service_sync(void)
 211 {
 212     struct netmsg_port_registration *reg;
 213     struct netmsg smsg;
 214
 215     netmsg_init(&smsg, &curthread->td_msgport, 0, netmsg_sync_func);
 216
 217     TAILQ_FOREACH(reg, &netreglist, npr_entry) {
 218         lwkt_domsg(reg->npr_port, &smsg.nm_lmsg, 0);
 219     }
 220 }
 221
 222 /*
 223  * The netmsg function simply replies the message.  API semantics require
 224  * EASYNC to be returned if the netmsg function disposes of the message.
 225  */
 226 static void
 227 netmsg_sync_func(struct netmsg *msg)
 228 {
 229     lwkt_replymsg(&msg->nm_lmsg, 0);
 230 }
 231
 232 /*
 233  * Generic netmsg service loop.  Some protocols may roll their own but all
 234  * must do the basic command dispatch function call done here.
 235  */
 236 void
 237 netmsg_service_loop(void *arg)
 238 {
 239     struct netmsg *msg;
 240
 241     while ((msg = lwkt_waitport(&curthread->td_msgport, 0))) {
 242         msg->nm_dispatch(msg);
 243     }
 244 }
 245
 246 /*
 247  * Call the netisr directly.
 248  * Queueing may be done in the msg port layer at its discretion.
 249  */
 250 void
 251 netisr_dispatch(int num, struct mbuf *m)
 252 {
 253     /* just queue it for now XXX JH */
 254     netisr_queue(num, m);
 255 }
 256
 257 /*
 258  * Same as netisr_dispatch(), but always queue.
 259  * This is either used in places where we are not confident that
 260  * direct dispatch is possible, or where queueing is required.
 261  */
 262 int
 263 netisr_queue(int num, struct mbuf *m)
 264 {
 265     struct netisr *ni;
 266     struct netmsg_packet *pmsg;
 267     lwkt_port_t port;
 268
 269     KASSERT((num > 0 && num <= (sizeof(netisrs)/sizeof(netisrs[0]))),
 270         ("netisr_queue: bad isr %d", num));
 271
 272     ni = &netisrs[num];
 273     if (ni->ni_handler == NULL) {
 274         kprintf("netisr_queue: unregistered isr %d\n", num);
 275         return (EIO);
 276     }
 277
 278     if ((port = ni->ni_mport(&m)) == NULL)
 279         return (EIO);
 280
 281     pmsg = &m->m_hdr.mh_netmsg;
 282
 283     netmsg_init(&pmsg->nm_netmsg, &netisr_apanic_rport, 0, ni->ni_handler);
 284     pmsg->nm_packet = m;
 285     pmsg->nm_netmsg.nm_lmsg.u.ms_result = num;
 286     lwkt_sendmsg(port, &pmsg->nm_netmsg.nm_lmsg);
 287     return (0);
 288 }
 289
 290 void
 291 netisr_register(int num, lwkt_portfn_t mportfn, netisr_fn_t handler)
 292 {
 293     KASSERT((num > 0 && num <= (sizeof(netisrs)/sizeof(netisrs[0]))),
 294         ("netisr_register: bad isr %d", num));
 295     netmsg_init(&netisrs[num].ni_netmsg, &netisr_adone_rport, 0, NULL);
 296     netisrs[num].ni_mport = mportfn;
 297     netisrs[num].ni_handler = handler;
 298 }
 299
 300 int
 301 netisr_unregister(int num)
 302 {
 303     KASSERT((num > 0 && num <= (sizeof(netisrs)/sizeof(netisrs[0]))),
 304         ("unregister_netisr: bad isr number: %d\n", num));
 305
 306     /* XXX JH */
 307     return (0);
 308 }
 309
 310 /*
 311  * Return message port for default handler thread on CPU 0.
 312  */
 313 lwkt_port_t
 314 cpu0_portfn(struct mbuf **mptr)
 315 {
 316     return (&netisr_cpu[0].td_msgport);
 317 }
 318
 319 lwkt_port_t
 320 cpu_portfn(int cpu)
 321 {
 322     return (&netisr_cpu[cpu].td_msgport);
 323 }
 324
 325 /* ARGSUSED */
 326 lwkt_port_t
 327 cpu0_soport(struct socket *so __unused, struct sockaddr *nam __unused,
 328             int req __unused)
 329 {
 330     return (&netisr_cpu[0].td_msgport);
 331 }
 332
 333 lwkt_port_t
 334 sync_soport(struct socket *so __unused, struct sockaddr *nam __unused,
 335             int req __unused)
 336 {
 337     return (&netisr_sync_port);
 338 }
 339
 340 /*
 341  * schednetisr() is used to call the netisr handler from the appropriate
 342  * netisr thread for polling and other purposes.
 343  *
 344  * This function may be called from a hard interrupt or IPI and must be
 345  * MP SAFE and non-blocking.  We use a fixed per-cpu message instead of
 346  * trying to allocate one.  We must get ourselves onto the target cpu
 347  * to safely check the MSGF_DONE bit on the message but since the message
 348  * will be sent to that cpu anyway this does not add any extra work beyond
 349  * what lwkt_sendmsg() would have already had to do to schedule the target
 350  * thread.
 351  */
 352 static void
 353 schednetisr_remote(void *data)
 354 {
 355     int num = (int)data;
 356     struct netisr *ni = &netisrs[num];
 357     lwkt_port_t port = &netisr_cpu[0].td_msgport;
 358     struct netmsg *pmsg;
 359
 360     pmsg = &netisrs[num].ni_netmsg;
 361     crit_enter();
 362     if (pmsg->nm_lmsg.ms_flags & MSGF_DONE) {
 363         netmsg_init(pmsg, &netisr_adone_rport, 0, ni->ni_handler);
 364         pmsg->nm_lmsg.u.ms_result = num;
 365         lwkt_sendmsg(port, &pmsg->nm_lmsg);
 366     }
 367     crit_exit();
 368 }
 369
 370 void
 371 schednetisr(int num)
 372 {
 373     KASSERT((num > 0 && num <= (sizeof(netisrs)/sizeof(netisrs[0]))),
 374         ("schednetisr: bad isr %d", num));
 375 #ifdef SMP
 376     if (mycpu->gd_cpuid != 0)
 377         lwkt_send_ipiq(globaldata_find(0), schednetisr_remote, (void *)num);
 378     else
 379         schednetisr_remote((void *)num);
 380 #else
 381     schednetisr_remote((void *)num);
 382 #endif
 383 }
 384